One hopeful area of accelerated hydrogen generation which has not been sufficiently explored and developed to date is the combined collection by polarization and pressure permeation of hydrogen molecules through selective permeable elements of various types. Only a slight amount of continual pressure exerted on the sealed electrolyte will be necessary to provide successive gas molecule passage through the porous electrode surfaces.
When the basic electrolysis function is combined with pressure-permeation, the gas molecules collect of each respective electrode surface and it is then possible to successively push the molecules through the electrode walls with a light pressure.
The electrode walls must be extremely thin and have a critical porosity factor in order to facilitate the passage of the hydrogen (and oxygen) molecules, to the total exclusion of the water molecules.
The present difficulties with this concept are that the actual gas yields will be relatively small per unit surface area of each electrode, with the possibility of progressive clogging of the permeable passages, or grids of the electrode surfaces.
A critical relationship exists for the electrode permeable passages (porosity), size, between the necessity for the total exclusion of the water molecule, and the need to maintain a maximum gas molecule transfer without any clogging.
Another critical aspect is the importance of maintaining adequate distributed electrical polarity means to densely attract the hydrogen and oxygen molecules within the passage path or grid.
This present square form of permeable electrode for the pressure electrolysis units has been evolved from the necessity of maintaining uniform electrical conductivity over the electrode surfaces for the electrolysis function of the pressure electrolysis units.
In the conventional electrolysis process it is known that unless each anode and opposite cathode surface is exactly flat and parallel, the electrical flow tends to pass across the shortest distance between the corresponding electrode surface a, and thereby progressively erode the local electrode metal at the "high" points.
This condition will materially shorten the useful service life of each electrode tube and cause the production of unpure gases at uneven flow rates.
The previously disclosed tubular electrodes will be less effective due to this problem, and will have shortened service life, unless some form of compensation means is provided in the fabrication of these round tubes.
Obviously, the present square-form of hollow electrode type will satisfy this operational condition when the multiple, identical square electrodes are set up in a square or rectangular-pattern within the pressure electrolysis cell units.
Various types of permeable electrode tubes have been evolved to support ad facilitate the development of the combined pressure-electrolysis process concept. The previous electrodes which were proposed involved the use of differing porosity ranges of thin-wall sintered tubes with external anti-caustic coatings. The metal selected for these tubes was either pure nickel or monel, since these are economically practical, and nearly noble, rather than platinum or palladium which are highly noble and therefore used for electrolysis electrodes, or for the permeation of the hydrogen molecule, respectively.
A later variation for the electrode material has been the use of fine wire mesh, seive cloth of about 400 mesh, which has the ability to prevent water molecule passage, while allowing the permeation of either hydrogen or oxygen molecules under pressurization.
The further development of the fine wire mesh cloth or screening for permeable electrodes appears most promising, since this approach would provide a near absolute minimum wall thickness, which is structurally and electrically sound.
A further benefit presented by the use of controlled diameter fine wire and mesh or grid opening size is that the fabrication techniques can be more closely controlled to produce uniform materials in production runs, compared with the more random sintered metal method in the 0.5 micron range.
The exact final mesh or porosity factor for the electrodes must be determined through successive testing and comparison, along with the percentage of electrolyte solution compatible with this combined process. Estensive life testing will be required to determine life-degrading and erosion factors, along with progressive passage restriction build-up.
The conceptral basis for the combined pressure-permeation electrolysis process is to accelerate the gas molecule passage through permeable elements, using external pressurizing means, as additional input energy means in lieu of a portion of the expensive electrical energy.
The substitution of some other convenient, low-cost energy source for a portion of the electrical input energy is attractive for further development effort to achieve the end results for the process concept.
The water-electrolysis function is basically clean and simple for obtaining both pure hydrogen and oxygen, and lends itself to various improvement modifications, such as the applying of heat energy, internal and external pressurization, and other energy forms.